I think you are very determined to remain on the question of truth or falsity!

Why not simply engage the passage with your imagination? Put aside for the moment whether to take it literally or metaphorically and contemplate its meaning. Metaphors become quite interesting when they're not sabotaged upfront with robotic disclaimers about their fictiveness.
Later (or simultaneously even if you are adept at mental calisthenics) you may return to the question of interpretation you pose. Having bothered with the momentary excercise, you may have gained something that folks who dismiss the expression as false out of hand will not.
One more try. If you are talking about statements like "
do unto others....." you can spend all the time you like in your imagination posing and countering ideas about how that works, whether it's meaningful, how it applies, whether it's changed your life or not; because that statement stripped of it's religious drag, does not posit a factual reality. It's a question of behavior and ethics, and in and of itself, says nothing tangible. It's philosophy.
But if you say, "
don't sin because you'll go to hell.." that statement does posit a factual reality, and a tangible punishment for disobedience and certainly must be evaluated in terms of it's veracity, because if it's fiction, it has no meaning. The only people who will take that seriously (and really not even a lot of them) are people who believe in a factual, not intellectual, not philosophical, not metaphysical, not imaginary, not fictitious, not metaphorical, God.
Let's count the direct assumptions of fact (and there are plenty of indirect to be had) in the original quote:
"
for god(1) so loved the world(2) that he gave his only begotten son(3) that whosoever believeth in him should not perish, but have everlasting life(4)"
If there is no god, there is no love of the world, no begotten son, no reason to believeth, and no everlasting reward.
What does that mean if even one of those things is false, and what great insights are derived from speculation over the motives of a non-existent deity, his non-existent son, and his promises of fictitious reward for faith?
That statement must be evaluated in terms of veracity or it has no meaning whatsoever.
Now you may certainly run about saying something like:
"...consider the ramifications of a fictitious God, who might love the world so much, that he sacrificed his virgin birth son, so people who he told to believe in his fictitious self, could have a non- existent immortality..."
What kind of response do you think you might get to that? Where is the insight?